Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Feb 23;4(1):49-52.
doi: 10.1098/rsbl.2007.0496.

Evolutionary associations between nectar properties and specificity in bird pollination systems

Steven D Johnson  1 , Susan W Nicolson
Affiliations

Evolutionary associations between nectar properties and specificity in bird pollination systems

Steven D Johnson et al. Biol Lett. .

Abstract

A long-standing paradigm in biology has been that hummingbirds and passerine birds select for different nectar properties in the plants they pollinate. Here we show that this dichotomy is false and a more useful distinction is that between specialized and generalized bird pollination systems. Flowers adapted for sunbirds, which are specialized passerine nectarivores, have nectar similar to that of hummingbird flowers in terms of volume (approx. 10-30 microl), concentration (approx. 15-25% w/w) and sucrose content (approx. 40-60% of total sugar). In contrast, flowers adapted to generalized bird pollinators are characterized by large volumes (approx. 40-100 microl) of extremely dilute (approx. 8-12%) nectar with minimal sucrose (approx. 0-5%). These differences in nectar traits are highly significant even when statistical analyses are based on phylogenetically separate pairwise comparisons between taxa. We present several hypotheses for the association between nectar properties and specificity in bird pollination systems.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Nectar properties (volume, concentration and sugar composition) in flowers pollinated by specialist versus generalist avian nectarivores. (a,c,e) Analyses of genera in the Americas (circles) and Africa (triangles) and (b,d,f) American Erythrina (open circles) and African Aloe (open triangles) species. Symbols are means±s.e. Sample sizes on (a,c,e) are numbers of genera and (b,d,f) represent species. Significance values (**p<0.01, ***p<0.001; n.s., not significant) are given for (a) a Mann–Whitney U-test and (b–f) main and interaction factors in two-way ANOVAs.
See this image and copyright information in PMC

References

    1. Baker H.G, Baker I. Chemical constituents of nectar in relation to pollination mechanisms and phylogeny. In: Nitecki M.H, editor. Biochemical aspects of evolutionary biology. University of Chicago Press; Chicago, IL: 1982a. pp. 131–171.
    1. Baker I, Baker H.G. Some chemical constituents of floral nectars of Erythrina in relation to pollinators and systematics. Allertonia. 1982b;3:25–37.
    1. Baker H.G, Baker I, Hodges S.A. Sugar composition of nectar and fruits consumed by birds and bats in the tropics and subtropics. Biotropica. 1998;30:559–586. doi:10.1111/j.1744-7429.1998.tb00097.x - DOI
    1. Brown J.H, Kodric-Brown A. Convergence, competition, and mimicry in a temperate community of hummingbird-pollinated flowers. Ecology. 1979;60:1022–1035. doi:10.2307/1936870 - DOI
    1. Bruneau A. Evolution and homology of bird pollination syndromes in Erythrina (Leguminosae) Am. J. Bot. 1997;84:54–71. doi:10.2307/2445883 - DOI

Publication types